You could try to install the add-in with an personal Microsoft account like an outlook.com account. If you do not have one, you could apply an outlook.com account for free via https://outlook.live.com/mail
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.